Colored picture and method of producing the same



` April 16, 1929.

J. cHRlsTENsEN 1,709,563

COLORED PICTURE AND METHOD OF PRODUCING THE SAME Filed Jan. 24, 1927 25 ing.

Patented Apr. 16,1929.

UNITED STATES .TENS HERMAN CHRISTENSEN, OIF,y HOLTE, DENMARK.

. 1 COLORED PICTURE AND METHOD F )PRODUCING THE SAME.

Application led January 24, 1927, Serial No. 163,017, and in Denmark,` January 25, 1926.

It is well knownthat colored pictures can.

of this kind are found in the trade. It has i also been attempted to use the same principle in pictures which are -to be seen in reflected light, it having been attempted to lo place a colored diapositive made in the manner outlined above upon a reflecting underopposite to the green elements g, and if the picture is seen inV transmitted light an ex- `fceedingly brilliant' and transparent green 5 inittcd light only, and photographic plates layer, but the'attained results have been poor, and it is the general belief that the method is appropriate for producing of pictures only which are to beseen in trans- 2o flected light, and the conditions which are to be fulfilled, according to practical experiments, when a favorable result shall be attained, are best understood by contemplating the annexed diagrammatical draw- Figure -1 shows a section through a colored screen picture placed on a .white reflecting layer of the commonly used `kind and serves only for explaining the inven tion. Figure 2 represents a section through a similar arrangement, the white layer having a better reflecting property according to the invention. Figures. 3 and 4 show urther modifications.

a: designates a section through a carrier of 3f, glass or Celluloid for the colored elements forming the layer b.l The elements canfor instance be red, green, and blue transparent particles which are mixed with each other. The layer o is a panchrornatic photographic 40 film, which can be found directly on the layer b or if necessary beseparated from the same through a thinlvarnish film k, if it is necessary to protect the colored elements' against the action of the aqueous baths with which the photographic film must be treated.

The picture is produced by the emulsion l film c becoming opa ue, owing to the silver reduced by the deve oper opposite vthe particles the colors of whichdo not correspond to that which the picture shall present on the red andthe blue elements as indicated on the'drawing while the film remains clear color can be obtained. y

If now a piece of white paper be laid in contact with the film c it was to be expected that this brilliant greeny picture could be seen in reflectedlight but in practicea very dark and unpure green picture only is seen. If the white paper referred to above be provided with`a cover of barium sulphate (the commercial baryta paper) or of calcium carbonate, white paint or another commonly used white reflecting substance, the result becomes somewhat better but is far from satisfactory. The matter is namely, that if the green light can enter through an appreciable distance Ainto the reflecting layer, bfqore it isreflected or returned, it is-to a considerable extent lost to the picture, it being in such case reflected partly to the sides and a smaller part ofthe saine only through the green color element, through which the light has entered. It is easily understood from Figure 1 of the drawing, that a light ray passing through the layer d until the point f will to a considerable extent not be refiected through the opening through which it entered, but the light will become lost through absorption in the red and blue neighbouring elements or the silver layer covering the same. If however, the

ray is refiected alreadyltl the pointh, in

Figure 2, it is seen that practically 'all of the light will be refiected through the admission aperture and thus be able to act on the eye. It is furthermore seen that the distance within which the livht must be reflected lfor mainly fpassing through the admission a erture is depending upon the diameter o the latter or of the colored element, and this distance should preferably be less than the diameter of the saidaperture. As the colored elements must be so small that they do not disturb the distinctness of thepicture, it is very small distancesfwhich are 1n question here, and at the common white reflecting substances the refiection takes place mainly from a greater depth.

In order to produce a white layer which reflects the light'. as near the surface as necessary I have'tried to use strongly light refracting substances such as titan white, lead tungstatc etc. mixed with an exceedingly small amount of a binder, and rather favorable results were attained. If the binder was practice having no coherence and being apt to fall off.

It` is known that such substances as nitrocellulose and acetyl cellulose after dissolu-- tion in appropriate solvents and after being poured out on a surface upon drying can yield a snow white cover, and such white layer has proved to give a rather favorable effect, but s'uch layers have also often a so small mechanical strength that they are useless in practice. I obtain a better result by adding to 100 cc. 4%-containing collodion 100 cc. toluene and 40 to 80 grams of a White pigment (lead white, titan white or the like). After drying a snow white film is obtained which has acertain mechanical resistance power and is'penetrated by numerous air fissures e as shown'in Figure 4 which augment the reflecting power. If these fissures are filled out for instance through soaking of the film in amyl acetate and drying of the same, the film apparently conserves its whiteness but the reflexion is effected in a much less degree from the surface itself, and when laid against a colored picture of the above mentioned kind a far less brilliant picture is obtained.

In lieu of the above named mixture of collodion 'and toluene other solutions of cellulose derivates can be used which are apt to be separated out in a white layer and form .air filled fissures on drying.

.It has shown to be' of little importance whether the reflecting layer be applied directly to the film c, for instance through pouring out upon the same and drying, or whether it is found between the layers a and b, as shown in Figure 3, thus under the layer of colored elements. In the last named case it, can be present before the exposure and development.

The said white layer can also be'made by pouring out on paper and drying, and it can be pasted on the picture after same is made ready. Care must be taken that the binder used does notfill up the air fissures in the layer. As a binder a weak rubber solution ,can advantageously be used. Figure 4 shows an arrangement of this kind, the air fissures being designated by e and the .paper by p.

In all of the structures shown in the drawing and herein described, the lm which comprises a layer of colored elements Z1 covered by a silver containing layer 0, is brought in contact with the reflecting layer d within the meaning of the claims, whether this be done by placing the layer Z on a separate backing p and then bringing the film in Contact therewith as in Figure 4, or by bringing the film in contact with the reflecting layer l by pouring same upon the filln Iand drying as previously described.

Having thus fully described my invention I claim as new and desire to secure by Let'- ters Patent: i

l. Method of producing colored photographic pictures to be seen in reflected light under use of a film comprising a layer of colored elements covered by a silver containing layer, consisting in bringing the said film in contact with a coherent white layer reflecting the main part of the light within a depth from the surface of the said white layer not exceeding the average diameter of the colored elements.

2'. Method of producing colored photographic pictures to be seen in reflected light under use of a film comprising a layer of colored elements covered by a silver containing layer, consisting in bringing the said film in contact with a layer of a cellulose derivate which is filled fissures.

3. Method of producing colored photographic pictures to be seen in reflected light under use of a film comprising a layer of colored elements covered by a silver containing layer, consisting in bringing the said film in contact with a layer of a cellulose derivate which is penetrated by numerous air filled fissures and contains a white pigment.

4. As an article of manufacture, a colored photographic picture to be seen by reflected light, comprising a layer of colored elements, a silver containing layer and a coherent white layer which reflects the main part of the light within a depth from the surface of the said white layer not exceeding the average diameter of the colored elements.

5. As an article of manufacture, a colored photographic picture to be seen by reflected light, comprising a layer of colored elements, a silver containing layer and a layer of a cellulose derivate which is penetrated by numerous air filled fissures.

6. As an article of manufacture, a colored photographic picture to be seen by reflected light, comprising a layer of-colored elements, a silver containing, layer and a layer of a cellulose derivate which is penetrated by numerous air filled fissures and contains a white pigment. l

In testimony whereof I have affixed my signature.

' J ENS HERMAN CHRISTENSEN.

penetrated by numerous air' 

